1. Field of the Invention
The present disclosure relates to transmission mechanisms, and more particularly to transmission mechanisms, such as in synchronization rings for variable vanes in gas turbine engines.
2. Description of Related Art
Traditionally, turbo fan engines for aircraft can include multiple stages of variable vanes to condition and guide airflow through the compressor and/or turbine sections. Variable vanes are configured to be pivoted about their respective vane axis to alter the angle of attack in order to optimize airflow characteristics for various operating conditions.
Variable vanes can be connected to a synchronization ring (sync ring), each by a respective vane arm connected to the stem of the respective vane. The sync ring can drive each variable vane counter-clockwise and/or clockwise around its respective longitudinal axis in order to adjust vane stage angle for a particular operating condition. Bell-crank style mechanisms are commonly used to convert the linear or rotational force and displacement of an actuator output shaft into an equivalent force and displacement suitable for driving the sync ring over the desired range of angular rotation. Depending on the desired range of angular displacement of the variable vanes, the limitation on input angle for bell-crank style mechanisms can limit the mechanical advantage that can be achieved through the bell-crank mechanism. This can ultimately limit the accuracy of angle of attack for traditional variable vane systems.
Such conventional methods and systems have generally been considered satisfactory for their intended purpose. However, there is still a need in the art for improved transmission mechanisms. The present disclosure provides a solution for this need.